Liquid detergent compositions are well known in the art. It is desirable that such compositions should have an attractive color as the compositions aesthetics is a key element in terms of consumer acceptance. A broad palette of dyes is available to the detergent formulator in order to address this need.
As an alternative, some compositions can be marketed without dyes, when the color of the product without dyes is sufficiently attractive.
However, it has been observed that in certain liquid detergent formulations, the color of the fresh product would not remain unchanged through prolonged periods. This represents a problem for the detergent manufacturer as detergents should be capable of withstanding prolonged periods of storage without undergoing significant alteration in any respect, including product aesthetics.
The reasons for this color alteration have not been precisely identified, but it is believed that such ingredients as alkanolamines are to some extent responsible for this phenomenon. Perfumes also appear to play a role, quite undefined because of the complex nature of perfumes. Thus, the extent of the color alteration phenomenon throughout time varies from one composition to the other.
It has been observed that this color alteration phenomenon occurs in detergent compositions, irrespective of the presence of a dye, i.e. it is the color of the "base" without the dye which is altered. Unfortunately, the presence of a dye does not always suffice to mask the color alteration phenomenon.
The above problem is more accute in "modern" liquid detergents as these detergents tend to be formulated as so-called concentrated liquid detergents wherein the interaction between the different ingredients and therefore the color alteration is favored. Also, these liquid concentrated detergents often encompass the use of alkanolamines which, as mentioned hereinabove, are to some extent responsible for the color alteration phenomenon.
It is thus an object of the present invention to formulate liquid detergent compositions which are stabilized against color alteration throughout prolonged periods.
In response to this object, the present invention proposes to formulate liquid detergent compositions which comprise low levels of materials yielding various sulfite ions in the detergent composition, as color-stabilizing compounds.
An advantage of the present invention is that it offers a color stabilization system which is efficient in all products where color alteration occurs, with or without dye. It is another advantage of the present invention that it proposes the use of simple chemicals, which are commercially available and relatively inexpensive.